Fetal growth disorders (both growth restriction and overgrowth) are common pregnancy complications, which carry an increased risk of adverse outcomes in the perinatal period and an increased risk of development of adult disease, including diabetes and cardiovascular disease. The placenta is a fetal-derived organ, whose proper development and function are pivotal in pregnancy success. Trophoblastic cells comprise the epithelial compartment of the placenta, and mediate nutrient/gas exchange functions and establishment of maternal blood flow into the feto-placental unit. Abnormal fetal growth has been associated with disorders of trophoblastic differentiation and function during early events in placentation, which lead to chronic feto-placental hypoxia. PPARgamma, a ligand-activated transcription factor and target of the thiazolidinedione family of anti-diabetic drugs, and Sirt1, a protein deacetylase and negative regulator of PPARgamma, have previously been shown to be involved in multiple facets of cell and tissue function, including differentiation nutrient-sensing, and metabolism. We have shown that Sirt1-PPARgamma signaling is specifically involved in trophoblast differentiation and hypoxia-induced trophoblast injury. In addition, both Sirt1-knockout and PPARgamma overstimulation have been shown to cause fetal growth restriction in mice. Finally, in human placentas, the expression and/or activity of PPARgamma and its endogenous ligands are altered in placentas associated with abnormal fetal growth, including fetal growth restriction, preeclampsia, and gestational diabetes. The goal of this proposal is to determine the mechanisms by which Sirt1-PPARgamma signaling contribute to trophoblastic differentiation, hypoxia-induced placental injury, and placenta-based fetal growth disorders. This project has the potential to identify therapeutic targets for these diseases, leading to a decrease in perinatal morbidity and mortality.